Butler was signed off the Cardinals' practice squad after splitting time this season on the active rosters of Arizona and Washington. He's appeared in eight NFL games, and was selected in the fifth round of the 2010 draft by Pittsburgh.

Welch has been a free agent since being released by Philadelphia before the start of this season. He was selected in the seventh round of the 2010 draft by New England. Welch has appeared in eight games split between the Patriots and St. Louis.

The signings, announced Wednesday, came a day after the Bills placed right tackle Erik Pears and cornerback Terrence McGee on season-ending injured reserve.